UV-curable resins used for chemical mechanical polishing pads

Abstract

The invention provides a UV-curable resin for forming a chemical-mechanical polishing pad comprising: (a) one or more acrylate blocked isocyanates; (b) one or more acrylate monomers; and (c) a photoinitiator. The invention also provides a method of forming a chemical-mechanical polishing pad using the UV-curable resin.

The invention claimed is: 
     
       1. A UV-curable resin for forming a chemical-mechanical polishing pad comprising:
 (a) an acrylate blocked isocyanate component, wherein the acrylate blocked isocyanate component comprises an acrylate blocking agent and an isocyanate terminated urethane prepolymer, wherein the acrylate blocking agents are selected from 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-(tert-butylamino) ethyl methacrylate (TBEMA), and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA), wherein the acrylate blocking agent and the isocyanate terminated urethane prepolymer form a capped prepolymer, and wherein there is a ratio of particular capped prepolymers in the acrylate blocked isocyanate component; 
 (b) one or more acrylate monomers; and 
 (c) a photoinitiator. 
 
     
     
       2. The UV-curable resin of  claim 1 , wherein the acrylate blocked isocyanate component comprises polyisocyanates. 
     
     
       3. The UV-curable resin of  claim 1 , wherein the isocyanate-terminated urethane prepolymers comprise aromatic prepolymers, aliphatic prepolymers, or combinations thereof. 
     
     
       4. The UV-curable resin of  claim 1 , wherein the acrylate blocking agents forming the capped prepolymers are 2-(tert-butylamino) ethyl methacrylate and 2-hydroxyethyl acrylate. 
     
     
       5. The UV-curable resin of  claim 4 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is greater than 50:50. 
     
     
       6. The UV-curable resin of  claim 5 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is 75:25. 
     
     
       7. The UV-curable resin of  claim 1 , wherein the one or more acrylate monomers are selected from isobornyl methacrylate (IBMA), 2-carboxyethyl acrylate (CEA), 2-hydroxyethyl acrylate (HEA), ethylene glycol dimethacrylate (EGDMA), neopentyl glycol dimethacrylate (NGDMA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA) and trimethylolpropane triacrylate (TMPTA). 
     
     
       8. The UV-curable resin of  claim 1 , wherein the photoinitiator is diphenylphosphine oxide (TPO). 
     
     
       9. The UV-curable resin of  claim 1  further comprising an additive selected from stabilizers, plasticizers, porogen fillers, pigments and combinations thereof. 
     
     
       10. A chemical-mechanical polishing pad comprising polymerized material formed from polymerization of the UV-curable resin of  claim 1 . 
     
     
       11. A method of forming a polishing pad comprising:
 (a) preparing a UV-curable resin comprising: 
 (i) an acrylate blocked isocyanate component, wherein the acrylate blocked isocyanate component comprises an acrylate blocking agent and an isocyanate terminated urethane prepolymer, wherein the acrylate blocking agents are selected from 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-(tert-butylamino) ethyl methacrylate (TBEMA), and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA), wherein the acrylate blocking agent and the isocyanate terminated urethane prepolymer form a capped prepolymer, and wherein there is a ratio of particular capped prepolymers in the acrylate blocked isocyanate component; 
 (ii) one or more acrylate monomers, and 
 (iii) a photoinitiator; 
 (b) exposing a thin layer of the UV-curable resin to UV light, initiating a polymerization reaction, and thus forming a thin layer of solidified pad material; 
 wherein the method does not include a thermal curing step. 
 
     
     
       12. The method of  claim 11 , wherein the isocyanate-terminated urethane prepolymers comprise aromatic prepolymers, aliphatic prepolymers, or combinations thereof. 
     
     
       13. The method of  claim 11 , wherein the acrylate blocking agents forming the capped prepolymers are 2-(tert-butylamino) ethyl methacrylate and 2-hydroxyethyl acrylate. 
     
     
       14. The method of  claim 13 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is greater than 50:50. 
     
     
       15. The method of  claim 14 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is 75:25. 
     
     
       16. The method of  claim 11 , wherein the one or more acrylate monomers are selected from isobornyl methacrylate (IBMA), 2-carboxyethyl acrylate (CEA), 2-hydroxyethyl acrylate (HEA), ethylene glycol dimethacrylate (EGDMA), neopentyl glycol dimethacrylate (NGDMA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA) and trimethylolpropane triacrylate (TMPTA). 
     
     
       17. The method of  claim 11 , wherein he photoinitiator is diphenylphosphine oxide (TPO). 
     
     
       18. The method of  claim 11 , further comprising an additive selected from stabilizers, plasticizers, porogen fillers, pigments and combinations thereof.